1. Field of the Invention
The present invention generally relates to a motor and a storage disk device using the motor.
2. Description of the Related Art
A storage disk drive such as a hard disk drive generally includes a spindle motor for rotationally driving the storage disk(s) (such spindle motor will be simply referred to as a “motor” hereinafter), and the motor may include a bracket attached to a housing of the storage disk drive to retain the motor thereon. A wire extending from an armature of the motor leads outside of the housing and/or the bracket via a through hole arranged therein and is soldered to a flexible printed circuit board (hereinafter simply referred to as a circuit board) attached to a bottom surface of the housing and/or the bracket.
In such motor, an insulating bush member may be inserted into the through hole provided to the housing and/or the bracket to maintain the insulation between the wire, and the housing and/or the bracket. The Japanese Examined Patent Application No. 3103609 describes a motor in which an insulating ring integrally formed with a bush to be inserted into a through hole is arranged axially below the armature. In general, as described in the Japanese Examined Patent Application No. 3103609, the housing and/or the bracket of the motor includes a recess on the bottom-outer surface, in which a portion of the bottom-outer surface is axially upwardly indented, to prevent the circuit board attached to the housing and/or the bracket from axially protruding the bottom-outer surface of the housing and/or the bracket.
Meanwhile, it is not desirable for an electric device with the motor to have a specific characteristic frequency. For example, in a storage disk drive such as a hard disk drive, it is not desirable that the storage disk drive has the characteristic frequency (Hz) which is a multiple of the number of revolutions per second of the data storage disk. The characteristic frequency of the electric device may be adjustable by changing the thickness of the casing of the electric device, but changing the design of the casing will cost a lot for such as renewing the dies used for manufacturing the casing. Further, to change the design of the casing may require changing the design of the other parts.